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Concrete dusting and water seepage

by Darlene
(Noblesville IN)

Q. We recently had a sunroom put on our existing patio that is 3 years old. The concrete people dug under the edges from the sides to pour 32 inch footers. They also had to add to the existing 8 foot patio to make it 10 foot. The new 2 feet of concrete connecting to the old is very dusty and can easily be scraped off with a finger. It also lets moisture seep in from the outside when it rains. What is wrong with this concrete and is it comprimising the 32 inch footers?

A. The problem with the surface is called dusting. This is good indication of a weak surface caused by pouring concrete to wet or finishing with too much moisture on the surface. The only thing you can do now for that is clean it well and put a sealcoat on it.
It's unlikely that the water seeping in is a problem with the concrete. It sounds like there are gaps where the base of the walls meet the concrete, which should have been addressed when the room was built. You need to seal it off on the oudside with caulk.
The footings are probably fine, you just have some minor surface issues with concrete.